1280809 has 4 divisors (see below), whose sum is σ = 1348240. Its totient is φ = 1213380.

The previous prime is 1280803. The next prime is 1280821. The reversal of 1280809 is 9080821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1280809 - 2⁹ = 1280297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1280803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33687 + ... + 33724.

It is an arithmetic number, because the mean of its divisors is an integer number (337060).

2^1280809 is an apocalyptic number.

1280809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1280809 is a deficient number, since it is larger than the sum of its proper divisors (67431).

1280809 is an equidigital number, since it uses as much as digits as its factorization.

1280809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67430.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 1280809 is about 1131.7283242899. The cubic root of 1280809 is about 108.5995744698.

The spelling of 1280809 in words is "one million, two hundred eighty thousand, eight hundred nine".